Heat Pumps - post here.

threeball

wofman27 wrote: »

Hi All,

Have been researching and pricing ATW, Geo and OFC Heating for the last few months (Donegal and Northwest), so far ATW is on par price wise with OFC (+Solar+HRV+Back Boiler), thats until i have to add solar to the ATW in order to comply with new regulations, which adds to the cost.

However we are running into problems with groundwork, a lot of rock breaking, which we had not budgeted for, we can cover this but now the engineer has come back with a design for foundations etc which is €19500 extra (which is stretching our budget above and beyond what we can afford). So we need to claw back money from somewhere.

Is there away to save money on the heating? Looks like were going to have to go OFH, with back boiler and Solar, want to avoid HRV as it costs around €5k. Is there a way to do this to comply with new regs? Or is there any other system or options out there?

The house is going to be insulated within an inch of its life and the final BER should be an A2 or A3.

Appreciate any feedback or advice on this

You're probably best to open a thread of its own for this question as most would only check here if researching heat pumps. I'd also look at posting in the BER forum

steifanc

I have an ashp with a 3 inch sand and cement screed . The first winter heating cycle takes about 6 hrs after that under a hour to feel heat maybe 2 for the house to get up to temp , 180mm insulation under the screed

dsparky

Hey all,

Building house and have to make choice between Unipipe F2040 12kw with indoor system VVM 320 or Dimplex A12M air to water heat pump complete with Dimplex ECS
250 HP ST 40A hotwater cylinder.

2700sq ft house, concrete slab each floor.

Have good deal available with unipipe system but not dimplex.

Stats are for dimplex system SFP 398.3 with rated capacity of 12.6kw and for unipipe SFP is 410 with rated capacity of 5.12kw

Any takers?


Thanks

Rushy Fields

Can anyone recommend someone to service my Nibe F1145 Geothermal heatpump and 300l cylinder. General overall service. PM me. Located near Galway Roscommon border.....

kerry bhoy

Hello, I am looking for info on air to water heat pumps. I am at roofing stage on new build and i will be using an ashp. It is a 200 sqm bungalow, with ufh, high level of insulation, triple glazing, mhrv . Need to get an A3 ber rating For part L . Looking for for info on running cost and general opinions from owners. Can pm info on the heat pump im using and company that is installing it if anyone is interested.

MOTM

kerry bhoy wrote: »

Hello, I am looking for info on air to water heat pumps. I am at roofing stage on new build and i will be using an ashp. It is a 200 sqm bungalow, with ufh, high level of insulation, triple glazing, mhrv . Need to get an A3 ber rating For part L . Looking for for info on running cost and general opinions from owners. Can pm info on the heat pump im using and company that is installing it if anyone is interested.

Energy savings trust did trials in the UK. Google "est heat pump field trial report"

BryanF

Threads merged

kerry bhoy

MOTM wrote: »

Energy savings trust did trials in the UK. Google "est heat pump field trial report"

Thanks

inchbyinch

Hi,

I am currently looking at a new 270sqm house build with a maximum instantaneous heat demand of circa 7kW. I'm installing a HP and looking to decide if I should go AS or GS.

My concerns around AS: (€22k including plumping)
1) Longevity of the unit - exposed to the elements and the site is very exposed (180m above sea level)
2) Thermal impact of ice on the heat exchanger, defrosting will obviously impact the COP but it's the creep fatigue I'm worried about.
I understand that the overall COP will be around the 2.3-2.7 mark (I estimate this will give me a €300 per annum saving on an oil system)

My only concern around GS is site suitability. (€22k including plumping excluding collector installation)
1) Looking at the GSI.ie website it would seem that most sites in Ireland are not suitable for GSHP with a horizontal collector. Primarily due to a lack of moisture in the soil between 1 & 2 meters. I'm in this catagory and so bore holes would seem to be the obvious solution.
If the GS achieved an overall COP of 3 the savings v oil would be €350 and @3.5 would be €400. I don't see any system beating the 3.5 mark considering how few did so in the energy trust survey.

Estimated cost to install the Geothermal collector
Horizontal €2,500
Vertical 200m @ €25 p/m plus bentonite €1000 - €6000

Questions to the learned minds in this forum -
1) Is the problem with soil types as real as it is reported to be? anyone out there with a horror story.
2) Does anyone have replacement costs for heat exchangers, outdoor compressors and fans to hand. I'm thinking one of these will fail in the life time of an AS unit (if not all). I would discount this cost against that of the collector installation
3) How could I find out if my site is suitable for a horizontal collector?

All feedback appreciated and feel free to correct anything that is utterly absurd above.

Note:
I built a simple model to calculate the difference between oil and HPs. I took the oil at 8.14c per kWh and electricity @ 16c per kWh. I assumed that most houses will need a light switch so left out cost of the standing charges on the electricity and assumed that an upgraded supply would not be needed. (you might be able to argue that this could discount the GS by €600 if a smaller unit only required a standard connection v an enhanced one). It's certainly not deadnuts but it is a good starting pointing.

Thanks,
Inchy

Condenser

inchbyinch wrote: »

Hi,

I am currently looking at a new 270sqm house build with a maximum instantaneous heat demand of circa 7kW. I'm installing a HP and looking to decide if I should go AS or GS.

My concerns around AS: (€22k including plumping)
1) Longevity of the unit - exposed to the elements and the site is very exposed (180m above sea level)
2) Thermal impact of ice on the heat exchanger, defrosting will obviously impact the COP but it's the creep fatigue I'm worried about.
I understand that the overall COP will be around the 2.3-2.7 mark (I estimate this will give me a €300 per annum saving on an oil system)

My only concern around GS is site suitability. (€22k including plumping excluding collector installation)
1) Looking at the GSI.ie website it would seem that most sites in Ireland are not suitable for GSHP with a horizontal collector. Primarily due to a lack of moisture in the soil between 1 & 2 meters. I'm in this catagory and so bore holes would seem to be the obvious solution.
If the GS achieved an overall COP of 3 the savings v oil would be €350 and @3.5 would be €400. I don't see any system beating the 3.5 mark considering how few did so in the energy trust survey.

Estimated cost to install the Geothermal collector
Horizontal €2,500
Vertical 200m @ €25 p/m plus bentonite €1000 - €6000

Questions to the learned minds in this forum -
1) Is the problem with soil types as real as it is reported to be? anyone out there with a horror story.
2) Does anyone have replacement costs for heat exchangers, outdoor compressors and fans to hand. I'm thinking one of these will fail in the life time of an AS unit (if not all). I would discount this cost against that of the collector installation
3) How could I find out if my site is suitable for a horizontal collector?

All feedback appreciated and feel free to correct anything that is utterly absurd above.

Note:
I built a simple model to calculate the difference between oil and HPs. I took the oil at 8.14c per kWh and electricity @ 16c per kWh. I assumed that most houses will need a light switch so left out cost of the standing charges on the electricity and assumed that an upgraded supply would not be needed. (you might be able to argue that this could discount the GS by €600 if a smaller unit only required a standard connection v an enhanced one). It's certainly not deadnuts but it is a good starting pointing.

Thanks,
Inchy

It would be far more common in Ireland for ground to be too wet rather than too dry for a horizontal GSHP. Vertical is normally only required because of water logged ground or very constrained sites.


Thermal shock is definitely an issue with ASHP's and the more economically built units will suffer coil failures because of it but icing and COP drop is far more of an issue.


It would be a very poor GSHP installation is it only reached a COP of 3 to 3.5. Get the right installer and the right product and a COP of 5 plus is easily achievable. I've read the EST report and its waffle with no real understanding off why the surveyed installs were performing so poorly.


If a compressor fails in a unit with the compressor outside its often cheaper to replace the entire unit as they're built so compactly compressor changes are a nightmare and take most of the day.


Horror stories with heat pumps are 99% of the time an installation issue. If its not installed correctly it won't matter how good the heat pump is. There are certain guidelines you must follow but most don't and end up with an underperforming system or a nightmare.

KCross

inchbyinch wrote: »

Hi,


I built a simple model to calculate the difference between oil and HPs. I took the oil at 8.14c per kWh and electricity @ 16c per kWh.

Thanks,
Inchy

Small point but alot of the electricity usage of a HP will be at nightsaver rate so it would be half the cost (8c/kWh) during those hours.

Condenser

KCross wrote: »

Small point but alot of the electricity usage of a HP will be at nightsaver rate so it would be half the cost (8c/kWh) during those hours.

But your day rate increases and I wouldn't recommend running a heat pump at night from a comfort point of view. Better to stick to day rate when HP is below 14kw.

BarneyMc

Condenser wrote: »

But your day rate increases and I wouldn't recommend running a heat pump at night from a comfort point of view. Better to stick to day rate when HP is below 14kw.

How does the comfort come into it? Do you mean the slab will be heated and release the heat during the night when not needed?

anoble66

Comfort probably refers to the noise of it kicking in and out. It's not that noisy but can definitely be heard in my (limited) experience.

BarneyMc wrote: »

How does the comfort come into it? Do you mean the slab will be heated and release the heat during the night when not needed?

Condenser

BarneyMc wrote: »

How does the comfort come into it? Do you mean the slab will be heated and release the heat during the night when not needed?

That's exactly what happens. The house temp will rise at night while you're under a duvet. Its not nice. A heat pump should be about more than just cost.
It also increases heat loss as the outside temp will be at its lowest while the inside temp is at its highest.

BarneyMc

Condenser wrote: »

That's exactly what happens. The house temp will rise at night while you're under a duvet. Its not nice. A heat pump should be about more than just cost.
It also increases heat loss as the outside temp will be at its lowest while the inside temp is at its highest.

See this is what I've been asking people about and never getting a straight answer. You always get the 'run it at night when the electricity is half price' line.

Having said that would a very well insulated house not just need a heating top up now and again so it wouldn't matter when the HP kicks in?

What do other 'HP People' do - run them at night and/or day?

Condenser

BarneyMc wrote: »

See this is what I've been asking people about and never getting a straight answer. You always get the 'run it at night when the electricity is half price' line.

Having said that would a very well insulated house not just need a heating top up now and again so it wouldn't matter when the HP kicks in?

What do other 'HP People' do - run them at night and/or day?

Lots run them at night so they can claim better running cost but end user comfort will suffer

inchbyinch

KCross wrote: »

Small point but alot of the electricity usage of a HP will be at nightsaver rate so it would be half the cost (8c/kWh) during those hours.

I did a model for that too and given the increase in the day cost of electricity and the increase in standing charge you only save about 1c per kWh if you use in excess of 14,000 kWh per annum and at least half of it is by night. Otherwise it's more expensive to run night rate. ESB previously (1980s) wanted to encourage night use of electricity to flatten the load and so it was heavily incentivised. However, the the auld Europeans came along and said we couldn't do that anymore as it encouraged electricity use (anticompetitive) for that reason the prices are far more balanced now.

KCross

Condenser wrote: »

Lots run them at night so they can claim better running cost but end user comfort will suffer

Condenser wrote: »

But your day rate increases and I wouldn't recommend running a heat pump at night from a comfort point of view. Better to stick to day rate when HP is below 14kw.

Just to clarify. I'm not saying run it at night exclusively. My HP, like everyone elses, is monitoring the indoor and outdoor climate 24/7 to ensure a constant temperature and the temp in my house is reasonably constant... I dont wake up at 3am thinking its too hot!

I have mine tweaked to fall back a degree or two in the hours leading up to night saver electricity and towards the end of night saver I have it "boosted" a degree or two.... its just to maximise the half price electricity but it doesnt run exclusively on night rate.

My main point was that the OP had used 16c/kWh as their "cost" for running a HP when in reality its much less than that based on my experience and from looking at the day/night usage meter connected directly to my HP.

I also run my other appliances (dishwasher, dryer etc) on night rate so you cant add all of the extra charges for having night rate onto the heat pump costs.

fred252

Folks, has anyone heard about a product recall from Daikin recently for one of their Heat pumps?

MENACE2010

All
my two pence.. on the night rate debate

this is from my supplier
11:00pm – 8:00am in the winter
12:00 midnight – 9:00am in the summer

So contrary of what has been stated on the post , every Pump can be configured to either block heating or fall back( eg it just maintains a lower temperature , mine is 18C during 9Am - 18 PM) .

So what I have done is this .. Block hot water generation from 09:00 AM till 23:00, have a reduced temperature from 09:00 am - till 18:00. This means the heating "can" kick in if and when the return loop detects a temperature differential and the rooms dive lower than 18% C.

what happens is that up till now ( 6th of October) i had the heating off entirely, now i have it set to automatic .. what governs the stuff above and it switches between heating and hot water when needed at the moment its fine , with the sun coming out now and again the temperature in the house is 19C without heating required

Now the second step.. the all important heat curve, this tells the heat pump what temperature to get to based on outside temperature and return loop temperature.. this is very fecking difficult to follow and I had to find a installer manual on the inter-webs to explain and even then its black magic

the bottom line is this , set your heat curve as low as possible , use a thermometer in the coldest room that is used often ( not the toilet) check the temperature there and the hottest room that is used . Here comes the challenge increase your heat curve until all your rooms are comfortable. at the moment the curve on my pump is flat 23 - 24 C i can increase the fall back and main temperature when needed

also use thermostats on your loops but again with underfloor heating this is not really a great help as the heat stored in the concrete will be slower in dissipation , eg switch the loop off and the concrete still will emit some heat but it will stop the pump earlier saving some cash, again here you need one loop on a higher stat as otherwise the pump will start fluctuating .. it wants to heat but i cannot get rid of the heat and it will stop .

challenges that I have is that on some occasions , in the winter the house gets a shot of sunshine while the floor is still hot what causes the house to " overheat" to 22 - 23 degrees C its rare but does happen.

So this and the fact (what I have posted in the past) every house is different in set-up what causes the heat pumps to act differently and efficiency between pumps and usage is different as well.
Its not all lost I'm a happy user of a Air source heat pump .. ( coming from houses with eye watering oil bills .. on avarage my bills through the entire year are 130 per month for everything at the moment ( taking into account all electricity bills for 12 months) for electricity.. I mean the lot.. washing machine , dryer,dishwasher, Xbox , TV, lights in the house and the heat recovery ventilation

Happy to come up with Idea's . .( next stop for me is to see if i can make it more intelligent .. ;o} )

BarneyMc

Great post MENACE! What is your floor makeup, i.e. sand/cement or screed and what depth?

MENACE2010

Hi
we have screed on top of (75mm) on top of 200mm EPS.. followed by a raft foundation ..

inchbyinch

Great post menace.

On the night the night rate I'd be interested to know your usage of night units v day units for the year? I think it might be on the bottom of the bill. I (roughly) calculated that on the usage you are at (€130 per month on a 50:50 split) you would be on the same bill on a standard connection and get a far better COP if heating was run during the day. If your over the 50% at night your winning. I make out you are using about 8000-8500 kWh of electricity per annum.

Assumptions made:
1 - 16c for standard rate
2 - 21c for Day electricity on night rate
3 - 10c per day for night rate
4 - standing charge standard rural €190 per annum
5 - standing charge night rate rural €240 per annum
6 - DAMN PSO levy:- €77 per annum
All including VAT

I'd be interested to see how far off the mark I am. Great post none the less. Came across a great blog last night on

ebuild.co.uk its the the-house-at-mill-orchard

He went away from intelligence as he wanted it simple so that anyone could understand it. Intelligent sounds like feedback control loops and that's a tricky pastime... More frustrating than golf I hear!

KCross

inchbyinch wrote: »

Assumptions made:
1 - 16c for standard rate
2 - 21c for Day electricity on night rate
3 - 10c per day for night rate
4 - standing charge standard rural €190 per annum
5 - standing charge night rate rural €240 per annum
6 - DAMN PSO levy:- €77 per annum
All including VAT

What company are you using to quote the unit rates. I believe I'm paying 16c day and 8c night inc vat and if I had a standard day only meter I'd be paying 15c so there is only 1c in the difference in the day rate.

From my reckoning all you need to do is use enough night rate to cover the increased standing charge and you break even. It doesn't take long to cover €50! I think your calculations are off.

inchbyinch

KCross wrote: »

My main point was that the OP had used 16c/kWh as their "cost" for running a HP when in reality its much less than that based on my experience and from looking at the day/night usage meter connected directly to my HP.

Hi Kcross,

Valid point on the 16 v 8 cent per unit. I was including VAT. However, I did have a reason for using the 16 cent per unit. I found that even when running alot at night (50%) your useage would need to be up near 10,000 units per year for the night rate to make sense. Even at that the savings are within the margin of error as your getting a lower COP from your AS heat pump at night so what you save on the swing you lose on the roundabout! I'll happily forward you the excel sheet and you can tweak for yourself if you want to PM me.

Either way I'm hoping to be well under the 10,000 units per year so it doesn't make sense for me to go night rate....hopefully more like 4-6000 but that is wishful thinking!!

inchbyinch

KCross wrote: »

What company are you using to quote the unit rates. I believe I'm paying 16c day and 8c night inc vat and if I had a standard day only meter I'd be paying 15c so there is only 1c in the difference in the day rate.

From my reckoning all you need to do is use enough night rate to cover the increased standing charge and you break even. It doesn't take long to cover €50! I think your calculations are off.

They sure are!!! I did the model using cheapest rates. It looks like the break even is more like 30% night rate use with savings past that. Apologies.

Over all @ 10000 kWhs the unit cost for the year on standard is 19.3c/kWh where as night rate works out at 16.6 c/kWh @ a 50:50 split.

KCross

inchbyinch wrote: »

They sure are!!! I did the model using cheapest rates. It looks like the break even is more like 30% night rate use with savings past that. Apologies.

Over all @ 10000 kWhs the unit cost for the year on standard is 19.3c/kWh where as night rate works out at 16.6 c/kWh @ a 50:50 split.

As an example, assuming you are a rural customer the standard rates on Airtricity right now are:

24hr rural: 19.08c/kWh and €204.04 standing charge

Night saver: 20.37c/kWh day, 10.09c/kWh night and €254.41 standing charge

If you take , as an example, 10000 units split 50/50 between day/night the figures I get including standing charge and VAT are:

24hr rural: €2112 or average of 21c/kWh
Night saver: €1777 or average of 17c/kWh

That's a €335 saving to have a day/night meter.

The actual bill you will get will be less, as everyone gets a discounted rate off the standard rate, once you ask for it!

A 50/50 split is roughly what I have in my house so night rate electricity is a no brainier as far as I'm concerned as I don't think it's recommended that you run your HP only during the day. Some of it needs to run at night to ensure the temp drop overnight is not too much and giving the HP too much to do during the day and as already stated you will be using night rate for other appliances anyway so you get other benefits to having night rate besides your HP.

John T Carroll

KCross wrote: »

As an example, assuming you are a rural customer the standard rates on Airtricity right now are:

24hr rural: 19.08c/kWh and €204.04 standing charge

Night saver: 20.37c/kWh day, 10.09c/kWh night and €254.41 standing charge

If you take , as an example, 10000 units split 50/50 between day/night the figures I get including standing charge and VAT are:

24hr rural: €2112 or average of 21c/kWh
Night saver: €1777 or average of 17c/kWh

That's a €335 saving to have a day/night meter.

The actual bill you will get will be less, as everyone gets a discounted rate off the standard rate, once you ask for it!

A 50/50 split is roughly what I have in my house so night rate electricity is a no brainier as far as I'm concerned as I don't think it's recommended that you run your HP only during the day. Some of it needs to run at night to ensure the temp drop overnight is not too much and giving the HP too much to do during the day and as already stated you will be using night rate for other appliances anyway so you get other benefits to having night rate besides your HP.

There certainly seems very big advantages in using night saver above, your Day/Night split would have to be as "bad" as 83/17 (actually 82.55/17.45) before starting to lose money on the night saver.

jpogorman

Hi,

Beginners air-to-water question:
For an air-to-water system, do you need an alternative hot water source such as solar for the summer months or can the air-to-water be configured to heat just the hot water in summer?

Thanks,
JP